Ten-speed transmission

ABSTRACT

A transmission is provided having an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices include clutches and brakes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/023,514, filed on Jan. 25, 2008, which is hereby incorporated in itsentirety herein by reference.

FIELD

The invention relates generally to a multiple speed transmission havinga plurality of planetary gear sets and a plurality of torquetransmitting devices and more particularly to a transmission having tenor more speeds, four planetary gear sets and a plurality of torquetransmitting devices.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A typical multiple speed transmission uses a combination of frictionclutches, planetary gear arrangements and fixed interconnections toachieve a plurality of gear ratios. The number and physical arrangementof the planetary gear sets, generally, are dictated by packaging, costand desired speed ratios.

While current transmissions achieve their intended purpose, the need fornew and improved transmission configurations which exhibit improvedperformance, especially from the standpoints of efficiency,responsiveness and smoothness and improved packaging, primarily reducedsize and weight, is essentially constant. Accordingly, there is a needfor an improved, cost-effective, compact multiple speed transmission.

SUMMARY

In an aspect of the present invention, a transmission is provided havingan input member, an output member, four planetary gear sets, a pluralityof coupling members and a plurality of torque transmitting devices. Eachof the planetary gear sets includes first, second and third members. Afirst interconnecting member continuously interconnects the third memberof the first planetary gear set with the third member of the fourthplanetary gear set. A second interconnecting member continuouslyinterconnects the first member of the first planetary gear set with thethird member of the second planetary gear set. A third interconnectingmember continuously interconnects the first member of the secondplanetary gear set with the second member of the third planetary gearset. A fourth interconnecting member continuously interconnects thefirst member of the third planetary gear set with the first member ofthe fourth planetary gear set. Six torque transmitting mechanisms areselectively engageable to interconnect one of the first, second, andthird members with at least one other of the first members, secondmembers, third members and a stationary member. The torque transmittingmechanisms are selectively engageable in combinations of at least threeto establish at least ten forward speed ratios and at least one reversespeed ratio between the input member and the output member.

In another aspect of the present invention, the first of the six torquetransmitting mechanisms is selectively engageable to interconnect atleast one of the third member of the first planetary gear set and thethird member of the fourth planetary gear set with the second member ofthe second planetary gear set.

In another aspect of the present invention, the second of the six torquetransmitting mechanisms is selectively engageable to interconnect thesecond member of the first planetary gear set with the second member ofthe second planetary gear set.

In yet another aspect of the present invention, the third of the sixtorque transmitting mechanisms is selectively engageable to interconnectat least one of the first member of the first planetary gear set thethird member of the second planetary gear set with the third member ofthe third planetary gear set.

In yet another aspect of the present invention, the fourth of the sixtorque transmitting mechanisms is selectively engageable to interconnectthe third member of the third planetary gear set with stationary member.

In yet another aspect of the present invention, the fifth of the sixtorque transmitting mechanisms is selectively engageable to interconnectthe second member of the first planetary gear set with the stationarymember.

In yet another aspect of the present invention, the sixth of the sixtorque transmitting mechanisms is selectively engageable to interconnectthe second member of the third planetary gear set with the stationarymember.

In yet another aspect of the present invention, the third member of thefirst, second, third and fourth planetary gear sets are sun gears, thesecond member of the first, second, third and fourth planetary gear setsare carrier members and the first member of the first, second, third andfourth planetary gear sets ring gears.

In yet another aspect of the present invention, the input member iscontinuously interconnected with at least one of the third member of thefirst planetary gear set and the third member of the fourth planetarygear set wherein the output member is continuously interconnected thesecond member of the fourth planetary gear set.

In still another aspect of the present invention, three of the torquetransmitting mechanisms are brakes and three of the torque transmittingmechanisms are clutches.

In still another aspect of the present invention, the stationary memberis a transmission housing.

Further objects, aspects and advantages of the present invention willbecome apparent by reference to the following description and appendeddrawings wherein like reference numbers refer to the same component,element or feature.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a lever diagram of an embodiment of a ten speed transmissionaccording to the present invention;

FIG. 2 is a diagrammatic illustration of an embodiment of a ten speedtransmission according to the present invention; and

FIG. 3 is a truth table presenting the state of engagement of thevarious torque transmitting elements in each of the available forwardand reverse speeds or gear ratios of the transmission illustrated inFIGS. 1 and 2.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

At the outset, it should be appreciated that the embodiments of the tenspeed automatic transmission of the present invention have anarrangement of permanent mechanical connections between the elements ofthe four planetary gear sets. A first component or element of a firstplanetary gear set is permanently coupled to a third component orelement of the second planetary gear set. A third component or elementof the first planetary gear set is permanently coupled to a thirdcomponent or element of the fourth planetary gear set. A first componentor element of the second planetary gear set is permanently coupled to asecond component or element of the third planetary gear set. A firstcomponent or element of the third planetary gear set is permanentlycoupled to a first component or element of the fourth planetary gearset.

Referring now to FIG. 1, an embodiment of a ten speed transmission 10 isillustrated in a lever diagram format. A lever diagram is a schematicrepresentation of the components of a mechanical device such as anautomatic transmission. Each individual lever represents a planetarygear set wherein the three basic mechanical components of the planetarygear are each represented by a node. Therefore, a single lever containsthree nodes: one for the sun gear, one for the planet gear carrier, andone for the ring gear. The relative length between the nodes of eachlever can be used to represent the ring-to-sun ratio of each respectivegear set. These lever ratios, in turn, are used to vary the gear ratiosof the transmission in order to achieve an appropriate ratios and ratioprogression. Mechanical couplings or interconnections between the nodesof the various planetary gear sets are illustrated by thin, horizontallines and torque transmitting devices such as clutches and brakes arepresented as interleaved fingers. Further explanation of the format,purpose and use of lever diagrams can be found in SAE Paper 810102, “TheLever Analogy: A New Tool in Transmission Analysis” by Benford andLeising which is hereby fully incorporated by reference.

The transmission 10 includes an input shaft or member 12, a firstplanetary gear set 14 having three nodes: a first node 14A, a secondnode 14B and a third node 14C, a second planetary gear set 16 havingthree nodes: a first node 16A, a second node 16B and a third node 16C, athird planetary gear set 18 having three nodes: a first node 18A, asecond node 18B and a third node 18C, a fourth planetary gear set 20having three nodes: a first node 20A, a second node 20B and a third node20C and an output shaft or member 22.

The input member 12 is coupled to the third node 14C of the firstplanetary gear set 14 and to third node 20C of the fourth planetary gearset 20. The output member 22 is coupled to the second node 20B of thefourth planetary gear set 20. The first node 14A of the first planetarygear set 14 is coupled to the third node 16C of the second planetarygear set 16. The third node 14C of the first planetary gear set 14 iscoupled to the third node 20C of the fourth planetary gear set 20. Thefirst node 16A of the second planetary gear set 16 is coupled to thesecond node 18B of the third planetary gear set 18. The first node 18Aof the third planetary gear set 18 is coupled to the first node 20A ofthe fourth planetary gear set 20.

A first clutch 26 selectively connects the third node 14C of the firstplanetary gear set 14 and the third node 20C of the fourth planetarygear set 20 with the second node 16B of the second planetary gear set16. A second clutch 28 selectively connects the second node 14B of thefirst planetary gear set 14 with the second node 16B of the secondplanetary gear set 16. A third clutch 30 selectively connects first node14A of the first planetary gear set 14 and the third node 16C of thesecond planetary gear set 16 with the third node 18C of the thirdplanetary gear set 18. A first brake 32 selectively connects the thirdnode 18C of the third planetary gear set 18 to a stationary member ortransmission housing 50. A second brake 34 selectively connects thesecond node 14B of the first planetary gear set 14 to the stationarymember or transmission housing 50. A third brake 36 selectively connectsthe second node 18B of the third planetary gear set 18 to the stationarymember or transmission housing 50.

Referring now to FIG. 2, a stick diagram presents a schematic layout ofthe embodiment of the ten speed transmission 10 according to the presentinvention. In FIG. 2, the numbering from the lever diagram of FIG. 1 iscarried over. The clutches and couplings are correspondingly presentedwhereas the nodes of the planetary gear sets now appear as components ofplanetary gear sets such as sun gears, ring gears, planet gears andplanet gear carriers.

For example, the planetary gear set 14 includes a sun gear member 14C, aring gear member 14A and a planet gear carrier member 14B that rotatablysupports a set of planet gears 14D (only one of which is shown). The sungear member 14C is connected for common rotation with input shaft ormember 12. The ring gear member 14A is connected for common rotationwith a first shaft or interconnecting member 42. The planet carriermember 14B is connected for common rotation with a second shaft orinterconnecting member 44 and a third shaft or interconnecting member46. The set of planet gears 14D are each configured to intermesh withboth the sun gear member 14C and the ring gear member 14A.

The planetary gear set 16 includes a sun gear member 16C, a ring gearmember 16A and a planet gear carrier member 16B that rotatably supportsa set of planet gears 16D (only one of which is shown). The sun gearmember 16C is connected for common rotation with first shaft orinterconnecting member 42. The ring gear member 16A is connected forcommon rotation with a fourth shaft or interconnecting member 48. Theplanet carrier member 16B is connected for common rotation with a fifthshaft or interconnecting member 52. The planet gears 16D are eachconfigured to intermesh with both the sun gear member 16C and the ringgear member 16A.

The planetary gear set 18 includes a sun gear member 18C, a ring gearmember 18A and a planet gear carrier member 18B that rotatably supportsa set of planet gears 18D (only one of which is shown). The sun gearmember 18C is connected for common rotation with a sixth shaft orinterconnecting member 54. The ring gear member 18A is connected forcommon rotation with seventh shaft or interconnecting member 56. Theplanet carrier member 18B is connected for common rotation with fourthshaft or interconnecting member 48 and with an eighth shaft orinterconnecting 58. The planet gears 18D are each configured tointermesh with both the sun gear member 18C and the ring gear member18A.

The planetary gear set 20 includes a sun gear member 20C, a ring gearmember 20A and a planet gear carrier member 20B that rotatably supportsa set of planet gears 20D (only one of which is shown). The sun gearmember 20C is connected for common rotation with input shaft or member12. The ring gear member 20A is connected for common rotation withseventh shaft or interconnecting member 56. The planet carrier member20B is connected for common rotation with output shaft or member 22. Theplanet gears 20D are each configured to intermesh with both the sun gearmember 20C and the ring gear member 20A.

The input shaft or member 12 is continuously connected to an engine (notshown) or to a turbine of a torque converter (not shown). The outputshaft or member 22 is continuously connected with the final drive unitor transfer case (not shown).

The torque-transmitting mechanisms or clutches 26, 28, 30 and brakes 32,34 and 36 allow for selective interconnection of the shafts orinterconnecting members, members of the planetary gear sets and thehousing. For example, the first clutch 26 is selectively engageable toconnect the input shaft or member 12 with the fifth shaft orinterconnecting member 52. The second clutch 28 is selectivelyengageable to connect the third shaft or interconnecting member 46 withthe fifth shaft or interconnecting member 52. The third clutch 30 isselectively engageable to connect the first shaft or interconnectingmember 42 with the sixth shaft or interconnecting member 54. The firstbrake 32 is selectively engageable to connect the sixth shaft orinterconnecting member 54 with the stationary element or thetransmission housing 50 in order to restrict the member 54 from rotatingrelative to the transmission housing 50. The second brake 34 isselectively engageable to connect the second shaft or interconnectingmember 44 with the stationary element or the transmission housing 50 inorder to restrict the member 44 from rotating relative to thetransmission housing 50. The third brake 36 is selectively engageable toconnect the eighth shaft or interconnecting member 58 with thestationary element or the transmission housing 50 in order to restrictthe member 58 from rotating relative to the transmission housing 50.

Referring now to FIG. 2 and FIG. 3, the operation of the embodiment ofthe ten speed transmission 10 will be described. It will be appreciatedthat transmission 10 is capable of transmitting torque from the inputshaft or member 12 to the output shaft or member 22 in at least tenforward speed or torque ratios and at least one reverse speed or torqueratio with quadruple overdrive. Each forward and reverse speed or torqueratio is attained by engagement of one or more of thetorque-transmitting mechanisms (i.e. first clutch 26, second clutch 28,third clutch 30, first brake 32, second brake 34 and third brake 36), aswill be explained below. FIG. 3 is a truth table presenting the variouscombinations of torque-transmitting mechanisms that are activated orengaged to achieve the various gear states. An “X” in the box means thatthe particular clutch or brake is engaged to achieve the desired gearstate. An “O” represents that the particular torque transmitting device(i.e. a brake or clutch) is on or active, but not carrying torque.Actual numerical gear ratios of the various gear states are alsopresented although it should be appreciated that these numerical valuesare exemplary only and that they may be adjusted over significant rangesto accommodate various applications and operational criteria of thetransmission 10. An example of the gear ratios that may be obtainedusing the embodiments of the present invention are also shown in FIG. 3.Of course, other gear ratios are achievable depending on the geardiameter, gear teeth count and gear configuration selected.

To establish a reverse gear, the first clutch 26, third clutch 30 andthird brake 36 are engaged or activated. The first clutch 26 connectsthe input shaft or member 12 with the fifth shaft or interconnectingmember 52. The third clutch 30 connects the first shaft orinterconnecting member 42 with the sixth shaft or interconnecting member54. The third brake 36 connects the eighth shaft or interconnectingmember 58 with the stationary element or the transmission housing 50 inorder to restrict the member 58 from rotating relative to thetransmission housing 50. Likewise, the ten forward ratios are achievedthrough different combinations of clutch and brake engagement, as shownin FIG. 3.

It will be appreciated that the foregoing explanation of operation andgear states of the ten speed transmission 10 assumes, first of all, thatall the clutches not specifically referenced in a given gear state areinactive or disengaged and, second of all, that during gear shifts,i.e., changes of gear state, between at least adjacent gear states, aclutch engaged or activated in both gear states will remain engaged oractivated.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A transmission comprising: an input member; an output member; first,second, third and fourth planetary gear sets each having first, secondand third members; a first interconnecting member continuouslyinterconnecting the third member of the first planetary gear set withthe third member of the fourth planetary gear set; a secondinterconnecting member continuously interconnecting the first member ofthe first planetary gear set with the third member of the secondplanetary gear set; a third interconnecting member continuouslyinterconnecting the first member of the second planetary gear set withthe second member of the third planetary gear set; a fourthinterconnecting member continuously interconnecting the first member ofthe third planetary gear set with the first member of the fourthplanetary gear set; and six torque transmitting mechanisms selectivelyengageable to interconnect one of the first, second, and third memberswith at least one other of the first members, second members, thirdmembers and a stationary member, and wherein the torque transmittingmechanisms are selectively engageable in combinations of at least threeto establish at least ten forward speed ratios and at least one reversespeed ratio between the input member and the output member.
 2. Thetransmission of claim 1 wherein a first of the six torque transmittingmechanisms is selectively engageable to interconnect at least one of thethird member of the first planetary gear set and the third member of thefourth planetary gear set with the second member of the second planetarygear set.
 3. The transmission of claim 2 wherein a second of the sixtorque transmitting mechanisms is selectively engageable to interconnectthe second member of the first planetary gear set with the second memberof the second planetary gear set.
 4. The transmission of claim 3 whereina third of the six torque transmitting mechanisms is selectivelyengageable to interconnect at least one of the first member of the firstplanetary gear set the third member of the second planetary gear setwith the third member of the third planetary gear set.
 5. Thetransmission of claim 4 wherein a fourth of the six torque transmittingmechanisms is selectively engageable to interconnect the third member ofthe third planetary gear set with stationary member.
 6. The transmissionof claim 5 wherein a fifth of the six torque transmitting mechanisms isselectively engageable to interconnect the second member of the firstplanetary gear set with the stationary member.
 7. The transmission ofclaim 6 wherein a sixth of the six torque transmitting mechanisms isselectively engageable to interconnect the second member of the thirdplanetary gear set with the stationary member.
 8. The transmission ofclaim 1 wherein the third member of the first, second, third and fourthplanetary gear sets are sun gears, the second member of the first,second, third and fourth planetary gear sets are carrier members and thefirst member of the first, second, third and fourth planetary gear setsring gears.
 9. The transmission of claim 1 wherein the input member iscontinuously interconnected with at least one of the third member of thefirst planetary gear set and the third member of the fourth planetarygear set wherein the output member is continuously interconnected thesecond member of the fourth planetary gear set.
 10. The transmission ofclaim 1 wherein three of the torque transmitting mechanisms are brakesand three of the torque transmitting mechanisms are clutches.
 11. Thetransmission of claim 1 wherein the stationary member is a transmissionhousing.
 12. A transmission comprising: an input member; an outputmember; first, second, third and fourth planetary gear sets each havingfirst, second and third members, the input member is continuouslyinterconnected with at least one of the third member of the firstplanetary gear set and the third member of the fourth planetary gear setwherein the output member is continuously interconnected the secondmember of the fourth planetary gear set; a first interconnecting membercontinuously interconnecting the third member of the first planetarygear set with the third member of the fourth planetary gear set; asecond interconnecting member continuously interconnecting the firstmember of the first planetary gear set with the third member of thesecond planetary gear set; a third interconnecting member continuouslyinterconnecting the first member of the second planetary gear set withthe second member of the third planetary gear set; a fourthinterconnecting member continuously interconnecting the first member ofthe third planetary gear set with the first member of the fourthplanetary gear set; a first torque transmitting mechanism selectivelyengageable to interconnect at least one of the third member of the firstplanetary gear set and the third member of the fourth planetary gear setwith the second member of the second planetary gear set; a second torquetransmitting mechanism selectively engageable to the second member ofthe first planetary gear set with the second member of the secondplanetary gear set; a third torque transmitting mechanism selectivelyengageable to interconnect at least one of the first member of the firstplanetary gear set the third member of the second planetary gear setwith the third member of the third planetary gear set; a fourth torquetransmitting mechanism selectively engageable to interconnect the thirdmember of the third planetary gear set with stationary member; a fifthtorque transmitting mechanism selectively engageable to interconnect thesecond member of the first planetary gear set with the stationarymember; and a sixth torque transmitting mechanism selectively engageableto interconnect the second member of the third planetary gear set withthe stationary member, and wherein the torque transmitting mechanismsare selectively engageable in combinations of at least three toestablish at least ten forward speed ratios and at least one reversespeed ratio between the input member and the output member.
 13. Thetransmission of claim 12 wherein the third member of the first, second,third and fourth planetary gear sets are sun gears, the second member ofthe first, second, third and fourth planetary gear sets are carriermembers and the first member of the first, second, third and fourthplanetary gear sets ring gears.
 14. The transmission of claim 12 whereinthe stationary member is a transmission housing.
 15. A transmissioncomprising: an input member; an output member; first, second, third andfourth planetary gear sets each having sun gears, carrier members andring gears, the input member is continuously interconnected with atleast one of the sun gear of the first planetary gear set and the sungear of the fourth planetary gear set wherein the output member iscontinuously interconnected the carrier member of the fourth planetarygear set; a first interconnecting member continuously interconnectingthe sun gear of the first planetary gear set with the sun gear of thefourth planetary gear set; a second interconnecting member continuouslyinterconnecting the ring gear member of the first planetary gear setwith the sun gear of the second planetary gear set; a thirdinterconnecting member continuously interconnecting the ring gear of thesecond planetary gear set with the carrier member of the third planetarygear set; a fourth interconnecting member continuously interconnectingthe ring gear of the third planetary gear set with the ring gear of thefourth planetary gear set; a first torque transmitting mechanismselectively engageable to interconnect at least one of the sun gear ofthe first planetary gear set and the sun gear of the fourth planetarygear set with the carrier member of the second planetary gear set; asecond torque transmitting mechanism selectively engageable tointerconnect the carrier member of the first planetary gear set with thecarrier member of the second planetary gear set; a third torquetransmitting mechanism selectively engageable to interconnect at leastone of the ring gear of the first planetary gear set the sun gear of thesecond planetary gear set with the sun gear of the third planetary gearset; a fourth torque transmitting mechanism selectively engageable tointerconnect the sun gear of the third planetary gear set withstationary member; a fifth torque transmitting mechanism selectivelyengageable to interconnect the carrier member of the first planetarygear set with the stationary member; and a sixth torque transmittingmechanism selectively engageable to interconnect the carrier member ofthe third planetary gear set with the stationary member, and wherein thetorque transmitting mechanisms are selectively engageable incombinations of at least three to establish at least ten forward speedratios and at least one reverse speed ratio between the input member andthe output member.
 16. The transmission of claim 15 wherein thestationary member is a transmission housing.